Merge feat/longform-pipeline: VAD long-form pipeline, opt-in (spec 001 workstream 3)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

# Conflicts:
#	docs/Architecture.md
#	docs/Decisions.md
#	src/App.tsx
#	src/index.css
#	src/lib/engine.ts
#	src/worker/inference.worker.ts
#	src/worker/protocol.ts
#	tests/engine.test.ts
#	tests/live-real-model.test.ts
#	tests/offline.md
#	tests/protocol.test.ts

docs/WorkBreakdown.md

@@ -423,6 +423,16 @@ Found in spec 001 workstream 6 (D-WS6a), open:
       (D-WS6a). Judging them needs a longer, harder Danish reference clip than
       this repo has.
 
+Found while building the long-form pipeline (spec 001 Goal 3, D-WS3a), 2026-10-29:
+- [ ] "Auto-detect" on the default (chunked) file path does not detect: with no
+      `language`, Transformers.js 4.2 logs "No language specified - defaulting to
+      English" and decodes Danish audio as an English translation (da_festuge WER
+      0.94 vs 0.14 with `da`). Long-form ("Skip silence") detects once and pins
+      the language; the chunked path is unchanged.
+- [ ] Spec 001's measurement fallback mentions a hint list of the names in
+      `en_alien`'s reference; `tests/meetingFixture.ts` returns audio + reference
+      only. Add the list when the vocabulary hint (workstream 2) lands.
+
 ## Recurring
 - [ ] Maintain `AGENTS.md`:
   - **Add a rule only in response to a real failure.** When an agent repeatedly